How many RPMs do you typically turn at highway speeds? I am running about 2500 at 55 mph. I guess that is not too high but it feels like the truck is straining to keep up that speed. Maybe I am just used to having overdrive.

 

That to me seems fast, my 2000 xlt 4X4 5.4 4r70 3.73 with 265/70R/17s at 55 mph is doing 1500 to 1600 RPMs

 

Thelt, what are the specs for your vehicle? Do you have overdrive & is it turned off?

 

I never run that slow. I have an 05 4x4 with auto and 3.73 rear. It runs at 2k at 70

 

Thats too high for 55 MPH... WAAAY more than any vehicle I've owned, at 55 MPH I'm around 14-1500 rpm

 

1000 rpm to 3500 rpm.

 

I turn 2 grand at 70 with a 4.6. make sure the little overdrive light on the shifter lever is not lit.

 

I run 1900 at 70mph with 3.55s and 265/70R17 tires. Make sure the O/D light is off, if it is blinking then you have a trans problem.

 

i run 2,000 at 70-75..

94 f150 351 E4OD 3:55, 235/75r15

 

You didn't say but I assume you have an older vehicle without overdrive, and depending on the rear gears, 2500 at 55 is not bad.

What year do you have?

 

Mine turns just a hair under 2,000 rpm at 70 mph.
Mine turns about 2500 in 3rd gear at 55 mph. It sounds to me like your truck isnt shifting into O/D.

 

I lied, I said I ran about 1500-1600 @55. Last night going home I checked, more like 1400 RPMs

 

I guess I should have gave my specs in the first post, sorry. It is an '89 F150 with a C6 three speed and a 351 V8. It may just be me, I have not driven a car without overdrive in a long time before I got this truck.

 

Hi Thelt - souds fine to me depending on your gearing & tires, is there anyone else here with his set-up?

 

If hes only got 4:11 rears, thats about right for a 3 speed.


My 2000 Ranger had 4:11's and it turned 2200 at 60mph in overdrive.